"no shared cipher" error with python and OpenSSL

Question

Server:

#!/usr/bin/env python

import SocketServer
import json
from OpenSSL import SSL
import os
import socket

TERMINATION_STRING = "Done"

CERTIFICATE_PATH = os.getcwd() + '/CA/certs/01.pem'
KEY_PATH = os.getcwd() + '/CA/private/key.pem'
CA_PATH = os.getcwd() + '/CA/cacert.pem'
print CA_PATH

def verify_cb(conn, cert, errnum, depth, ok):
    print('Got cert: %s' % cert.get_subject())
    return ok

class SSLThreadingTCPServer(SocketServer.ThreadingTCPServer):
    def __init__(self, address, handler):
        SocketServer.ThreadingTCPServer.__init__(self, address, handler)

        ctx = SSL.Context(SSL.SSLv23_METHOD)
        ctx.set_verify(SSL.VERIFY_PEER | SSL.VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb)

        ctx.use_privatekey_file(KEY_PATH)
        ctx.use_certificate_file(CERTIFICATE_PATH)
        ctx.load_verify_locations(CA_PATH)

        self.socket = SSL.Connection(ctx, socket.socket(self.address_family, self.socket_type))
        self.socket.set_accept_state()

        self.server_bind()
        self.server_activate()

        print "Serving:", address[0], "on port:", address[1]



class MemberUpdateHandler(SocketServer.StreamRequestHandler):
    def setup(self):
        self.connection = self.request
        self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
        self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)

        print self.client_address, "connected"

    def handle(self):
        data = ""
        while True:
            data += self.request.recv(1024).encode('utf-8').strip
            if data[-4:] == "Done":
                print "Done"
                break

            dataStrings = data.split(' ')
            for item in dataStrings:
                print item

if __name__ == "__main__":
    ADDRESS = 'localhost'
    PORT = 42424
    HOST = (ADDRESS, PORT)

    s = SSLThreadingTCPServer(HOST, MemberUpdateHandler)
    s.serve_forever()

Client:

#!/usr/bin/env python

from OpenSSL import SSL
import socket
import os

HOST = 'localhost'
PORT = 42424
ADDRESS = (HOST, PORT)

CERTIFICATE_FILE = os.getcwd() + '/CA/certs/02.pem'
KEY_PATH = os.getcwd() + '/CA/clientKey.pem'
CA_PATH = os.getcwd() + '/CA/cacert.pem'

def verify_cb(conn, cert, errnum, depth, ok):
    print('Got cert: %s' % cert.get_subject())
    return ok

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

ctx = SSL.Context(SSL.SSLv23_METHOD)
ctx.set_verify(SSL.VERIFY_PEER, verify_cb)
ctx.use_certificate_file(CERTIFICATE_FILE)
ctx.use_privatekey_file(KEY_PATH)
ctx.load_verify_locations(CA_PATH)

sslSock = SSL.Connection(ctx, sock)
sslSock.connect(ADDRESS)

items = "this is a test Done"

sslSock.sendall(items)

sslSock.close()

Error on the server side:

Error: [('SSL routines', 'SSL3_GET_CLIENT_HELLO', 'no shared cipher')]

Error on the client side:

OpenSSL.SSL.Error: [('SSL routines', 'SSL23_GET_SERVER_HELLO', 'sslv3 alert handshake failure')]

I have a feeling that I am missing something simple, but have been unable to pin it down. I have found several questions exactly like mine in various places, but none have been answered. I am new to network programming and would greatly appreciate any help.

Using Ubuntu 10.04 and python 2.6

Answer 1

Try to change order to this:

...
ctx.use_certificate_file(CERTIFICATE_PATH)
ctx.use_privatekey_file(KEY_PATH)
...

When I use this order in my code I get meanfull error message on server start (not on client connect):

Traceback (most recent call last):
  File "src/server_main.py", line 230, in <module>
    s = SSLClientsAuthServer()
  File "src/server_main.py", line 134, in __init__
    ctx.use_privatekey_file (self.config.value['SERVER_KEY'])
OpenSSL.SSL.Error: [('x509 certificate routines', 'X509_check_private_key', 'key values mismatch')]

This is because I have really used webserver.key that not corresponds webserver.crt:

$ openssl x509 -text -in certs/webserver.crt
Certificate:
Data:
    Version: 3 (0x2)
...
            Modulus:
                00:a1:b6:e3:ce:53:3d:c9:96:a6:06:1d:3e:ae:34:
....


$ openssl rsa -text -in keys/webserver.key
Private-Key: (2048 bit)
modulus:
    00:b7:34:61:d7:c7:0d:2b:5c:57:26:d0:8d:7a:04:
....

Make sure you have used the same RSA key.